1. Technical Field
The invention relates to a continuous method for conditioning material for food and/or semi-luxury consumables, in which the material is introduced through an entrance into a hyperbarically pressurized conditioning chamber, where it is treated with a conditioning agent, and extracted again from the conditioning chamber at an exit. In the following, this method shall be called pressure-conditioning for short. The invention further relates to a device for pressure-conditioning material for food and/or semi-luxury consumables.
The material which is pressure-conditioned in accordance with the invention can on the one hand be a tobacco material, in particular tobacco stem material, or on the other hand a granular food commodity such as for example cereals and legumes, i.e. amylaceous products such as for example maize, rice, wheat, peas and soy beans.
2. Description of the Related Art
In the field of tobacco processing, a number of proposals exist in accordance with the prior art for conditioning tobacco material, such as for example stems or strips. What is meant here by conditioning is the necessary procedural treatment of tobacco material before it is cut or also shredded. The conditioning process substantially consists of a thermotechnical treatment, so-called moistening with the media of steam, water and possibly with casing media. The process serves to make the tobacco material more resilient to the inevitable formation of small parts and dust during the comminuting process. If the tobacco material has a high entry moistness, conditioning can also mean de-moistening the tobacco.
In accordance with the standard method in accordance with the prior art, preparing stems substantially consists of moistening, accompanied by desired heating. Heated stems benefit the penetration process of the water into the interior of the stem stalks. The raw stems are thus partially moistened in a number of stages, wherein steam is sprayed in the corresponding apparatus and water is added. Furthermore, material is also stored in boxes in accordance with the prior art. These storage times can be up to 24 hours. This disadvantageously results in a large requirement of time and space for the boxes.
Conditioning is successful if the stem has a high degree of flexibility and exhibits no discernible surface moistness. Surface moistness significantly disrupts cutting, since slippery pieces of stem elude an undisrupted formation of “stem cake” in the cutting apparatus and cause hollow spaces.
Furthermore, slippery stems are more easily torn out of the stem cake while being cut by the cutting knife and thus incompletely cut. These incompletely cut stems, called knockouts, are to be avoided when cutting.
Burley stems in particular tend to form soapy surfaces. This behavior is counteracted by setting sufficient storage times. Very often, the material is rolled before being cut, which causes an improved packing structure in the cake.
Rolling is also significantly disrupted by slippery stem surfaces.
In addition to the standard conditioning processes described at the beginning, other conditioning methods for tobacco material are also known. WO 99/23898, for instance, shows a plant which serves to treat and/or moisten tobacco material with casing medium, wherein the apparatus is arranged vertically, such that the tobacco material free-falls vertically from top to bottom through a pipe in which it is sprayed with the corresponding medium. Other conditioning systems in which is treated with the conditioning medium in free-fall through a chamber are known from U.S. Pat. No. 5,740,817, WO 90/06695, DE 197 34 364 A1 and DE 100 38 114 A1.
The problem which arises with the systems cited above is that a uniform and thorough penetration of moistness, such as is for example necessary for tobacco stems, cannot be optimally realized in the relatively short dwelling time of the tobacco material while it falls downwards in the conditioning chamber. While such apparatus operate quickly, they do not prepare the tobacco material as thoroughly as would be desirable.
A device for treating tobacco material is known from WO 87/07478, in which the tobacco material is introduced into a chamber, where it is transported, lying on a conveyor belt, from the entrance to the exit, while pressurized steam is supplied to the chamber. Because the tobacco material comes to rest piled up on the conveyor belt, layers lower down are disadvantageously more poorly moistened than tobacco material lying on top, which overall results in not completely satisfactory conditioning.
For a different, non-generic field of tobacco processing, namely nitrate depletion, a device is known from DE 195 35 587 C2 in which tobacco is input into an obliquely arranged casing in which a water bath is situated. A slight pressure burden prevails in the casing, and the tobacco stems are transported by means of a conveying screw from the water bath to the exit of the casing.